This invention relates to high heat polyethersulfone compositions, methods for their preparation, and articles made therefrom.
Polyethersulfones are a commercially important family of high performance, high temperature thermoplastics. These polymers are of interest to many industries because of their combination of high ductility, high heat resistance, hydrolysis resistance in steam and hot water environments and good overall chemical resistance. In addition, polyethersulfones are frequently transparent, unlike many non-transparent, semi-crystalline materials which are also used in high temperature applications.
Polyethersulfones can be produced by a variety of methods. For example, U.S. Pat. Nos. 4,108,837 and 4,175,175 describe the preparation of polyarylethers and in particular polyarylethersulfones. U.S. Pat. No. 6,228,970 describes the preparation polyarylethersulfones with improved polydispersity and reduced oligomer content. British patent GB 1,264,900 teaches a process for production of a polyethersulfone comprising structural units derived from 4,4′-biphenol, bisphenol-A, and bis (4-chlorophenyl)sulfone.
Currently available polyethersulfones typically possess an intermediate level of heat resistance. Commercially important polyarylethersulfones include polysulfone (PSU), polyphenylsulfone (PPSU) and polyethersulfone (PES). PSU is a well-known high temperature amorphous engineering thermoplastic resin exhibiting a glass transition temperature (Tg) of about 185° C., high strength, stiffness and toughness over a temperature range of from about −100° to 150° C. PSU has an Izod impact strength value (Notched Izod value) of about 69 Jm−1 (1.3 ft-lb/in). PSU was commercially introduced in 1965 by the Union Carbide Corporation and is commercially available as UDEL® polysulfone from Solvay Advanced Polymers LLC. Another versatile polyarylethersulfone polymer is polyphenylsulfone (PPSU). PPSU is commercially available from Solvay Advanced Polymers LLC under the trademark of RADEL R®. It has a Tg of 220° C. and an Izod impact strength value of about 700 Jm−1 (13 ft-lb/in).
In various applications it would be highly desirable to produce polyethersulfones with increased heat resistance (higher glass transition temperatures) relative to known polyethersulfones, while maintaining a useful level of impact strength.